Water Supply
The total volume of water on earth is 1.4 billion km³.
97% of this is saltwater.
Only 3% is fresh water.
The sources of fresh water are estimated as:
68.7% is in the form of ice or permanent snow.
31% is stored underground and elsewhere.
Only 0.3% is contained in lakes and rivers.
Currently, the total usable fresh water supply for humans and ecosystems represents less than 1% of all fresh water resources. Water desalination provides less than 1% of the total demand.
This supply is unevenly distributed around the world. As climate change continues, water trading among countries and states is increasingly becoming a part of public debate in national and international forums. Water is a commodity, and tools are needed to clarify discussion of its value and tradability.